Automatic oil separator control for refrigerating systems



Dec. 22, 1936. c. R. NEESON 2,065,195

AUTOMATIC OIL SEPARATOR CONTROL FOR REFRIGERATING SYSTEMS Filed July 13, 1933 2 Sheets-Sheet l INVE-NTOR' C. FF. Neesan v A ORNEY Dec. 22, 1936. Q R NEESQN 2,065,195

AUTOMATIC OIL SEPARATOR CONTROL FOR REFRIGERATING SYSTEMS I Filed July 13, 1933 2 Sheets-Sheet 2 INVENTOR C. I? lyeaia/z Patented Dec. 22, 1936 STATES AUTOMATIC 01L sEPAaA'ron'cou'raoL roa nnmraana'rmo SYSTEMS Charles R. Neeson, New Rochelle, N. Y., assignor to Baldwin-Southwark Corporation, a corporation of Delaware Application July 13, 1933, Serial No. 680,181

11 Claims.

This invention relates generally to an improved system for separating oil from a refrigerating system and of automatically discharging the separated oil into the compressor, the invention being particularly adapted for refrigerating systems of relatively small capacity such as are used for air conditioning apparatus for homes or ofiices.

It is one object of my invention to provide improved means whereby oil may be separated from either or both the discharge or suction sides of a compressor and automatically returned to the compressor crankcase.

.A further object is to provide an oil strainer preferably in the discharge line from the compressor and to utilize the discharge pressure for automatically forcing the separated oil into the compressor crankcase but automatically substantially preventing flow of gaseous refrigerant from the high pressure side to the crankcase.

A further object is to provide in combination with my improved system a compressor in which low pressure is maintained in the crankcase which serves'as air-oil sump. and in one embodiment of the invention to havean automatic valve control submerged in the oil of said sump whereby heat of the valve casing will assist in driving oif refrigerant that may become dissolved in or mixed with the oil;

30 In, one specific'aspect of the invention the above objects .are accomplished by providing in combination with the high pressure discharge side of the compressor an oil strainer. adapted to feed-oilthrough a high pressure float controlled 35 valve that will permitsubstantially free flow of the separated-oil under. pressure from the discharge line intothe crankcase andyet will be automatically closed it a relatively small amount of. gaseous. refrigerant comes over with the separatedoil; the float having suitable provision to permit this small, amount of refrigerant gas to escape automatically after a. prede termined length I of; time thereby to allow further flow of any oilthat might have been separated during 45: the temporary closure of the automatic valve mechanismipf Other ob ects?'andi'advantagesmll be more apparent totho se skilled in theart from the following escription of 'the acqqmpanying drawings inwhic hf' V 1 is an elevationalview of a. motor driven compressor unit embo'dying'imy improved system;

" Figizii's a perspective of the oil separator and discharge pipes arranged in such a manner as to present a unitary structure;

Fig. 3 is an enlarged view of the float valve cooperating with my improved system:

Fig. 4 is a modified arrangement wherein the valve is disposed outside of the compressor crankcase;

Fig. 5 is an enlarged sectional view of the valve used in Fig. 4, being similar however in its internal structural and functional aspects to the valve shown in Fig. 3.

In the illustrated embodiments of the invention which are shown herein merely for the purpose of disclosing certain specific forms among others that the invention might take, I employ any suitable type of compressor generally indicated at l, preferably of the self-contained hermetically sealed motor-compressor unit type. This particular unit is preferably of the vertical shaft type having a low pressure crankcase, acting as an oil sump 2, in communication with the intake side of the compressor. The compressor shown has two opposed radial cylinders 3 and 4 but it will of course be understood that any number of cylinders or arrangement thereof may be used.

Leading from the compressor cylinders 3 and I is a common usual high pressure discharge pipe 5 preferably curved to conform to the compressor casing which in cross-section is cylindrical. The ends 6 and 6a of this pipe and an intermediate pipe 6b secured thereto are bent upwardly so that 6 and 6b may be moved up into suitable vertical discharge openings in the cylinders 3 and l and the end So moved into a vertical opening of a suitable compressor unloader casing '60 adapted to by-pass the discharge side into the suction side during the unloading operation. The unloader is not part of the present invention except to illustrate the manner of connecting the unitary discharge and oil pipe construction. The upwardly projecting portions of this unit are welded, soldered or otherwise suitably hermetically sealed in said openings. A preferably. vertical pipe I is welded or otherwise secured to pipe 5 for communication therewith substantially midway thereof. This pipe extends upwardly adjacent to an intermediate point of the vertical axis motor casing la. andterminates in any usual or suitable type of oil separator generally indicated at 8. The remote position of separator 8 from the discharge line 5 allows more effective oil separation due to *a certain amount of cooling effect produced by riser pipe 1. --Any oil mixed with the'gaseous refrigerant flowing from thecom-pressor through pipe 1 will beseparated out in separator 8, the gas then passing on through a pipe 1' to a usual conend bent upwardly at 912 for connection to the The arrangement above described provides an extremely compact and efi'icient self-contained unitary structure including if desired certain or all of pipes 5, I and 9 and separator 8, thereby not only permitting this unit to be built and tested before assembling with the compressor but also due to said portions 6, 6a, 6b and 9a all extending in the same direction, specifically upwardly, the unit may be effectively assembled with the fixed compressor elements by a. simple straight movement. A further desirable advantage of this improved construction is that the curvature in pipe 5 permits the entire unit to be sufliciently flexible to easily 'adjust itself to any irregularities or stresses during or after the fastening of ends 6, 6a, 6b and 9a in the cylinders 3 and 4, unloader 6e and valve II). It will of course be understood that said vertical portions of the discharge pipe may be fewer or more in number as may be desired for making necessary connections or for omitting certain connections now shown.

Valve Ill comprises preferably an inverted cup shell ll extending through a suitable opening in the sump wall 2 and welded or otherwise suitably secured thereto. A lower closure cap l3 may be threaded, welded or otherwise suitably secured in the lower end of easing II and provided with a suitable opening l4 preferably centrally located to telescopically receive pipe 9a which is then s01- dered, welded or otherwise secured in position. The opening l4 terminates preferably in a portion I5 which normally projects above the lower open edge of a float Hi. This relation .is effected specifically by an, annular recess l1 into which float l6 extends although other arrangements may be used such as will be described in connection with Fig. 4, or by pipe 9a projecting into said float.

The float I6 is an inverted cup shell having a relatively small leak p'ort l8 in its upper closed end. The upper end also carries a suitable fulcrum member l9 pivotally supported on one end of a lever 20 whose other end is pivotally carried by and between a pair of hooks 2| projecting downwardly from and secured to a member 22. This member is removably fastened to the top inner surface of shell I I. A ball 23 is suitably supported on link 20 with substantially limited movement relative thereto to permit automatic adjustment and alignment of the ball with respect to its seat, this seat being formed at the lower edges of an opening 24 provided preferably in removable bushing 25. The opening 24 communicates directly with the sump 2.

Operation-Upon discharge of refrigerant from the compressor cylinders such as 3 and 4 a certain amount of oil may be entrained with the gaseous refrigerant. This mixture flows through oil separator 8 thus allowing the refrigerant gas to pass through pipe 1 while the oil separated therefrom flows downwardly through pipe 9 under the high discharge pressure, and thence upwardly through opening M of valve member ID, into the lower open portion of float l5 and thence downwardly and upwardly around the lower edge thereof as indicated by the arrow 26. So long as oil flows in the manner indicated without the presence of any gas, float l6 will remain in its down position due to gravity, thereby allowing the accumulated oil in casing II to flow past the ball 23 and through restricted opening 24 to crankcase 2 under reduced pressure. However, if the oil separation is temporarily sufficiently complete so that no further oil drains through pipe 9, then gaseous refrigerant will flow through pipe 9 and opening l4 into float l6. Due to the casing being filled with oil the float is thus provided with a liquid seal around its lower open edge thereby causing any slug of gas to pass upwardly through the liquid within the float to the top thereof. Thereupon the float rises to close port 24 through the action of fulcrum l9, lever-20 and pivot 2| moving ball 23 into contact with the seat around port 24 and thus temporarily prevent discharge of either gas or oil into sump 2. However, the gas which has accumulated in float IE will gradually leak through port I 8 into the upper part of valve casing l0 until the float IE will fall by its own weight and thus open port 24. This will then allow the accumulated gaseous refrigerant to escape through port 24 into the crankcase to be recompressed and will also allow further flow of anyoil into the valve casing that might have been separated out during the period in which port 24 was closed by valve 23. However, if further oil has not been separated in trap 8, then anotherslug of refrigerant gas will pass over through pipe 9 and again actuate float Hi to close port 24. The amountof refrigerant gas employed in this system-is so relatively small that the efliciencyof the system is not materially affected.

If it is further desired to'eflect the utmost elimination of possible oil in the system, I have provided another oil separator 26 interposed in the compressor suction line 21. A drain pipe "leads from the bottom of separator 26 to the compressor crankcase or sump 2.

Modification.-In the modification of Figs. 3 and 4, it is seen that the same general arrangement of oil separator 8 and trap I 0 is employed except that the trap I0 in this modifieda'rrangement is disposed outside of the sump 2 and also has a cup shaped shell 30 with its open end at the top. The unitary pipe and separator structure of Figs. 1 and 5 may be employed but for purposes of this modification, the elements are arranged as shown. Corresponding parts of the two forms are given the same reference numbers with the numbers primed for Figs. 3 and 4. Pipe 9a connects to shell 30 so as to have the same relation to float It as shown in Fig. 2. A fulcrum, lever and ball valve elements l924 are the same for-both Figs. 3 and 4 except that in Fig. 4 bushing 24 is secured in a removable cap 3| provided with a chamber 32 from which a pipe '33 leads to the compressor sump 2. The operation of this modification is the same as the preferred form.

From the foregoing disclosures it is seen that I have provided a relatively simple and yet highly effective arrangement whereby any oil, mixed with the high pressure gaseous refrigerant flowing to the condenser, will be efficiently separated from the gas and automatically returned to the compressor system by utilizing the high pressure without liability of any substantial quantity of refrigerant gas flowing into the compressor whenever the return of separated oil to the crankcase has been temporarily completed.

It will of course be understood by those skilled in the art that various changes may be made in the details of construction and arrangement of parts without departing from the spirit of the invention as set forth in the appended claims.

Iclaim:

1. The combination in a refrigerating system comprising, a compressor having a high pressure discharge line, a low pressure oil sump, an oil separator in said discharge line, means for allowing communication from said separator to said sump during operation of said compressor and for causing separated oil to be returned to the sump solely under the high pressure refrigerant gas, and means for temporarily interrupting said communication automatically when the return of oil has been completed. I

2. The combination set forth in claim 1 further characterized in that said automatic means has provision for opening automatically after being closed for a predetermined period thereby to allow further return to the sump of any separated oil.

3. The combination in a refrigerating system comprising a compressor having a high pressure discharge line, a low pressure oilsump, an'oil separator in said discharge line, means for allowing communication from said separator to said sump whereby separated oil may be returned to the sump under the high pressure refrigerant gas, and means for temporarily interrupting said communication automatically by the flow of high pressure refrigerant gas from said separator to said sump when the return of oil has been completed.

4. The combination in a refrigerating system comprising a compressor, an oil sump, a high pressure discharge line, an oil separator in said line, and a gas operated float controlled valve communicating with said separator to allow flow of oil therefrom to said sump and to substantially prevent fiow of refrigerant gas through said separator to said sump.

5. The combination in a refrigerating system comprising a compressor having a discharge line and an oil sump, an oil separator in said line, means allowing communication from said separator to said sump for the return of oil thereto, and gas operated means for automatically temporarily interrupting any flow of gaseous refrigerant from said separator to said sump and to allow gradual leakage of refrigerant gas to reestablish further flow of oil from the separator to the sump. 6. The combination in a refrigerating system comprising a compressor having adischarge line and an oil sump, an oil separator in said line, means allowing communication between said separator and sump, and a float operated valve for controlling said communication, said valve having a casing projecting into said sump so as to be submerged in the oil therein and give up heat thereto.

7. The combination in a refrigerating system comprising a compressor having an oil sump and refrigerant suction and discharge lines, an oil separator in said suction line and an oil discharge line allowing constant communication between said separator and said sump, an oil separator disposed in said refrigerant discharge line and having communication with said sump, and means .for temporarily interrupting said latter communication automatically in accordancewith flow of refrigerant gas from said latter separator to said sump.

8. The combination in a refrigerating system .be assembled with the compressor and valve by a simple straight movement.

9. The combination in a refrigerating system comprising a compressor having a plurality of cylinders, an oil sump, and an automatic valve I to permit oil to flow to said sump but substantially prevent flow of gaseous refrigerant thereto; and a unitary structure including a curved compressor discharge pipe adapted for connection to each of said cylinders, a vertical pipe connected to and extending upwardly from said curved pipe,

an oil separator carried by and communicating with said vertical pipe, and an oil return pipe carried by and projecting down from said oil separator and communicating with said sump to return separated oil thereto, said curved discharge pipe and oil return pipe having their free ends extending in substantially the same direction and said cylinders and automatic valve having openings to receive said ends.

10. The combination in a refrigerating system comprising a compressor having a plurality of radially disposed cylinders, an oil sump and an automatic valve associated with said sump to permit how of oil thereto but substantially prevent flow of gaseous refrigerant to said sump; and a unitary structure including a curved compressor discharge pipe to commonly connect said cylinders, a vertical pipe communicating with said curved pipe and supported thereby, an oil separator carried by and connected to said vertical pipe, a pipe extending downwardly from said 011 separator and communicating with said sump to return separated oil thereto, the ends of said curved pipe and return pipe being bent upwardly in the same general direction and said cylinders and automatic valve having openings extending downwardly thereby to receive said upwardly extending ends by a simple straight movement of said unitary structure.

11. The combination in a refrigerating system comprising, a compressor having a high pressure discharge line, a low pressure oil sump, an oil separator in said discharge line, means forming a passage whereby said separator'is adapted to communicate with said sump during operation of said compressor for causing separated oil to be returned to the sump solely under the high pressure refrigerant gas, and means for controlling said communicating passage automatically upon flow of fluid therethrough whereby the flow of refrigerant gas under high pressure is substantially restricted upon completion of the dischargeof separated oil into said sump. C. R. NEESON. 

